Projected studies include: (1) Characterization of the purified proline hydroxylase from earthworm subcuticular epithelium; (2) Excretion of total and free 3-hydroxyproline in human urine; (3) Peptide distribution of urinary 3-hydroxyproline; (4) Hydroxylation of proline residues in basement membrane collagen; (5) Metabolic degradation of 3-hydroxyproline in mammals; (6) Synthesis and properties of collagen-like polypeptides containing proline, 4-hydroxyproline or 3-hydroxyproline.